1. Field of the Invention
The present invention relates to an improvement in a hydraulic mechanism for a vehicle.
2. Description of Background Art
A conventional hydraulic mechanism for a vehicle is known wherein a single hydraulic piston is operated by two operating forces. See, for example, Japanese Patent Laid-open No. Hei 9-254771.
FIGS. 1 and 4 of Japanese Patent Laid-open No. Hei 9-254771 set forth a front wheel brake operating lever 11 swingably supported on a support shaft 77 together with an arc-shaped conjunction member 76 with one end of the conjunction member 76 placed in contact with an end part of a piston rod 58 provided to be integral with a master piston 57 in a front wheel master cylinder 13 and the other end of the conjunction member 76 being placed in contact with an end part of a piston rod 70 provided to be integral with a piston 69 in a front wheel slave cylinder 17.
The front wheel master cylinder 13 is connected to a brake caliper of a front wheel brake BF through a hydraulic oil passage 67.
A rear wheel brake operating lever 121 is connected to a rear wheel master cylinder 141, which is connected to the front wheel slave cylinder 17 through a hydraulic oil passage 54.
The front wheel master cylinder 13 and the front wheel slave cylinder 17 are connected to each other through connecting arm parts 55a, 55b protruding from the front wheel master cylinder 13 side and connecting arm parts 68a, 68b protruding from the front wheel slave cylinder 17 side.
The front wheel brake operating lever 11 produces an operating hydraulic pressure in the front wheel master cylinder 13. The hydraulic pressure is transmitted through the hydraulic oil passage 67 to the brake caliper of the front wheel brake BF and caliper pistons 15 provided inside the brake caliper clamp a brake disk therebetween, whereby the front wheel is braked.
In addition, when the rear wheel brake operating lever 121 is operated, hydraulic pressure is generated in the rear wheel master cylinder 141 and the hydraulic pressure is transmitted through the hydraulic oil passage 54 to the front wheel slave cylinder 17. Thus, the hydraulic pressure generated in the front wheel slave cylinder 17 causes the piston rod 70 to push one end of the conjunction member 76, so that the conjunction member 76 is swung about the support shaft 77, and the other end of the conjunction member 76 pushes the piston rod 58 in the front wheel master cylinder 13, whereby hydraulic pressure is generated in the front wheel master cylinder 13. Thus, the front wheel is braked in the same manner as above-mentioned.
The front wheel master cylinder 15 and the front wheel slave cylinder 17 are connected to each other through the connecting arm parts 55a, 55b and the connecting arm parts 68a, 68b. Thus, a manufacturing error or assembly error may change the positional relationship between the front wheel master cylinder 15 and the front wheel slave cylinder 17, resulting, for example, in a change in the moving amount of the master piston 57 in the front wheel master cylinder 15 upon movement of the piston 69 in the front wheel slave cylinder 17. There is a need for a structure in which the positional relationship between the master cylinder and the slave cylinder for use in a vehicle as above-mentioned will not be changed.
In addition, according to the above-mentioned structure, the front wheel master cylinder 15 and the front wheel slave cylinder 17 are spaced away from each other by a distance corresponding to the connecting arm parts 55a, 55b and the connecting arm parts 68a, 68b, so that the hydraulic mechanism will be large in overall size and will occupy a large space in the vehicle.